As development of optical technology, various optical elements are applied in many different fields. In a lighting field, an optical lens is used to change a path of light emitted by a light source to achieve desired optical effect. For example, a surface of the lens is designed as a curved surface (concave surface or convex surface) to converse or diffuse light passing therethrough. However, the surface of the lens is usually a single curved surface, when the lens is used in a near-field light field, the lens fails to adjust path of light only by structure of itself.